The present application relates to semiconductor manufacturing, and more particularly to methods of fabricating a silicon germanium (hereinafter “SiGe”)-on-insulator (hereinafter “SGOI”) material in which thermal mixing of either a layer of silicon formed on a germanium-on-insulator (hereinafter “GeOI”), or a layer of germanium formed on a silicon-on-insulator (hereinafter “SOT”) is employed.
Crystalline Si1-xGex is attractive for both bipolar and metal oxide semiconductor field effect transistor (hereinafter “MOSFET”) applications. High performance p-channel MOSFETs consisting of a SiGe channel are in use in 22 nm complementary metal oxide semiconductor (hereinafter “CMOS”) devices. Increasing germanium (hereinafter “Ge”) concentration in Si1-xGex to very high values, such as x>70% Ge, allows higher carrier mobilities for both electron and holes. However, Si1-xGex epitaxially grown on a single crystal Si substrate is metastable and relaxes by generating misfit dislocations and stacking faults when its thickness exceeds a certain value, known as the critical thickness. This thickness decreases exponentially as x increases in Si1-xGex.
Thus, there is a need for providing a method that allows for the formation of high structural quality Si1-xGex-on-insulator material, in particular Si1-xGex-on-insulator materials that contain x>50%, that avoids the problems associated in the prior art.